Method of infusing sulfur and resulting composition
A method utilizing microwave energy to incorporate sulfur onto carbon, prepare cathode material for lithium sulfur battery applications, and the compositions resulting therefrom is disclosed.
1. A method of forming a carbon/sulfur composite, comprising:
a) placing a porous carbon/sulfur mixture into a closed pressure reactor vessel;
b) placing the closed pressure reactor vessel in a microwave oven;
c) subjecting the porous carbon/sulfur mixture to a microwave heat source;
d) raising the temperature to a few hundred ° C. by subjecting the porous carbon/sulfur mixture to a microwave power of at least 500 Watts for a sufficient time to vaporize the sulfur and bind the sulfur to the carbon; and
e) lowering the temperature of the porous carbon and sulfur vapor to below the melting point of sulfur, thereby condensing sulfur vapor inside pores of the porous carbon and forming a carbon/sulfur composite containing sulfur bound to carbon.
2. The method of claim 1 , wherein the carbon/sulfur composite is a lithium sulfur battery carbon electrode.
3. The method of claim 1 , wherein the sulfur in the carbon/sulfur mixture is elemental sulfur, sulfide, disulfide or a sulfur-containing compound.
4. The method of claim 1 , wherein the carbon in the carbon/sulfur mixture is a carbon-containing material.
5. The method of claim 1 wherein the carbon in the carbon/sulfur mixture is carbon black, graphite, carbon fiber, carbon nanotube, fullerene, graphene, graphene oxide, activated carbon, pyrolytic carbon, polymer-derived carbon or combinations thereof.
6. The method of claim 1 , wherein the temperature of the porous carbon/sulfur mixture is heated up to a temperature ranging from a few hundred to more than 2000° C.
7. The method of claim 1 , wherein the carbon/sulfur composite comprises sulfur in an amount of from 60 wt. % to 95 wt. %.
8. The method of claim 1 , wherein the carbon/sulfur composite comprises carbon in an amount of from 5 wt. % to 40 wt. %.